private Expr MatchAssignment()
{
Expr expr = MatchEquality();
if (Match(TokenType.EQUAL))
{
Token equal = ReadPrevToken();
Expr value = MatchAssignment();
if (expr.GetType() == typeof(VariableExpr))
{
Token name = ((VariableExpr)expr).name;
return(new AssignExpr(name, value));
}
else if (expr.GetType() == typeof(GetExpr))
{
GetExpr gexpr = (GetExpr)expr;
return(new SetExpr(gexpr.obj, gexpr.name, value));
}
ReportError("Invalid assignment target.");
}
return(expr);
}
private Expr Call()
{
var expr = Primary();
while (true)
{
if (Match(TokenType.LeftParen))
{
expr = FinishCall(expr);
}
else if (Match(TokenType.Dot))
{
var name = Consume(TokenType.Identifier, "Expect property name after '.'.");
expr = new GetExpr(expr, name);
}
else
{
break;
}
}
return(expr);
}
private Expr MatchCallExpr()
{
Expr expr = MatchPrimary();
while (true)
{
if (Match(TokenType.LEFT_PAREN))
{
List <Expr> args = new List <Expr>();
do
{
if (Check(TokenType.RIGHT_PAREN) == false)
{
if (args.Count >= 8)
{
ReportError("Cannot have more then 8 arguments.");
}
args.Add(MatchExpression());
}
} while (Match(TokenType.COMMA));
Token paren = Consume(TokenType.RIGHT_PAREN, "Expect ')' after arguments.");
expr = new CallExpr(expr, paren, args);
}
else if (Match(TokenType.DOT))
{
Token name = Consume(TokenType.IDENTIFIER, "Expect property name after '.'.");
expr = new GetExpr(expr, name);
}
else
{
break;
}
}
return(expr);
}
protected abstract object MatchGetExpr(GetExpr getExpr);
protected override object MatchGetExpr(GetExpr expr) => Resolve(expr.Object);
public virtual void Visit(GetExpr expr)
{
}
public override void Visit(GetExpr expr)
{
expr.obj.Accept(this);
}
public override void Visit(GetExpr expr)
{
expr.obj.Accept(this);
AddStr("." + expr.name.lexeme);
}
